The present invention is generally directed to the generation of potable water. More particularly, the present invention is directed to articulated wave energy conversion system (AWECS) with reverse osmosis (RO) membranes to generate potable water.
Desalinization plants are located around the world, and are operated using electricity to pressurize the incoming source water. Depending on the location, there may be pretreatment requirements to optimize the influent for processing through the RO membranes.
The U.S. Department of Interior (DOI) funded the Subfloor Water Intake Structure System (SWISS), currently utilized in desalination desalinization plants in California and Japan. The SWISS approach is to install a permanent subfloor well/intake system for the source-water for the traditional shore structures. The in-situ sand provides the filtration media. See, for example, Lovo, Robert, “Initial Evaluation of the Subfloor Water Intake Structure System (SWISS) vs. Conventional Multimedia Pretreatment Techniques,” Assistance Agreement No. 98-FC-81-0044, Desalination Research and Development Program Report No. 66, U.S. Dept. of Interior, May 2001, whose disclosure is incorporated by reference herein in its entirety.
Ocean wave-energy conversion is directed to the exploitation of ocean wave energy to produce energy in one or more of four forms, those being hydraulic, pneumatic, mechanical or electrical. See McCormick, “Ocean Wave Energy Conversion,” published by Wiley-Interscience, New York (1981, reprinted by Dover Publication, Long Island, N.Y. in 2007). The articulated-barge wave-energy conversion system dates back to the 1970's when both Sir Christopher in the United Kingdom and Glen Hagen of the United States suggested the system. The system was studied in the late 1970's by P. Haren (1978) at MIT. He found that the optimum articulated-barge configuration was a three-barge system. In the 1980's, Dr. Peter McCabe showed that the efficiency of the three-barge system could be substantially improved by suspending an inertial-damping plate below the center barge. Dr. McCabe, then, produced a prototype of the system, coined the McCabe Wave Pump (MWP), which was deployed and studied in the Shannon Estuary for approximately nine years. See, U.S. Pat. No. 5,132,550 (McCabe). The MWP was primarily designed as a producer of potable water.
Ocean Energy Systems (OES) is in the business of designing and manufacturing articulated-barge systems to produce potable water by RO desalinization of sea water. U.S. Patent Publication No. 2009/0084296 (McCormick), describes a system directed to a wave-powered device having enhanced motion making use of an AWECS. See also U.S. Patent Publication No. 2010/0320759 (Lightfoot, et al.). The AWECS basically comprises a forward barge, a rear barge and an intermediate or center barge, all of which arranged to float on a body of water having waves. The barges are hingedly coupled together so that they can articulate with respect to each other in response to wave motion. The AWECS also includes high-pressure pumps which straddle and pivotably connect the barge-pairs, e.g., at least one pump connects the forward barge and the intermediate barge, and at least another pump connects the rear barge and the intermediate barge. The pumps are designed to draw in the water through a pre-filter, pressurize the water, and deliver the water to an on-board RO desalinization system. That system includes an RO membrane. As an incoming wave makes contact with the forward barge first, the hydraulic fluid in the pump(s) coupled between the forward barge and the center barge are driven in a first direction; as the wave continues, the hydraulic fluid in the pump(s) coupled between the rear barge and the center barge are driven in a second opposite direction. The end results are bi-directional hydraulic pumps.
In U.S. Provisional Patent Application Ser. No. 61/707,206, filed on Sep. 28, 2012, there is disclosed an AWECS arranged for producing electrical energy from the wave energy. To that end, it makes use of an AWECS similar to that described above, except that it also makes use of a commercially-available rotary-vane pump to drive a generator to produce the electricity. In particular, the invention of that Provisional Application entails a floating device having a first portion (e.g., a first barge) movably coupled (e.g., hinged) to a second portion (e.g., a second barge); at least one hydraulic or pneumatic pump (e.g., a linear pump) coupled between the first portion the said second portion, the hydraulic pump driving a hydraulic fluid therein when the first portion moves with respect to the second portion due to wave energy. A fluid rectifier is provided in the AWECS and is in fluid communication with the at least one hydraulic or pneumatic pump, that generates a unidirectional hydraulic or pneumatic fluid flow. A rotary vane pump is coupled to the fluid rectifier. The rotary vane pump uses the unidirectional flow to generate a rotational motion via a drive member. A rotating electrical generator (e.g., a DC generator) is coupled to that drive member, so that the drive member causes the rotating electrical generator to generate electricity when the drive member is rotating.